docs: def equalizer(self, frequency, q=1.0, db=-3.0):
          """equalizer takes three parameters: filter center frequency in Hz, "q"
          or band-width (default=1.0), and a signed number for gain or
          attenuation in dB.
  
          Beware of clipping when using positive gain.
          """
          self.command.append('equalizer')
          self.command.append(frequency)
          self.command.append(str(q) + 'q')
          self.command.append(db)
          return self